Combined plumb-bob and rule.



No. 821,371. i

PATENTED MAY 22, 1906. R. M DONALD. COMBINED PLUMB'BOB AND RULE.

. APPLIO m r :0 IA 19 REYNOLDS MCDONALD, OF ST. LOUIS, MISSOURI.

COMBINED PLUIVlB-BOB AND RULE- Specification of Letters Patent.

Patented May 22, 1906.

Application filed January 30,1905- Serial No. 243,200-

To all whom it may concern.-

Be it known that I, REYNOLDS MCDONALD, a citizen of the United States, and a resident of St. Louis, Missouri, have invented certain new and useful Improvements in a Combined Plumb-Bob and Rule, of which the following is a specification containing a full, clear, and exact description, reference being had to the accompanying drawings, forming a part hereof.

My invention relates to improvements in combined plumb-bobs and rules; and it consists of the novel features herein shown, described, and claimed.

The object of my invention is to provide an instrument which will be very accurate and reliable in use.

In the drawings, Figure 1 is a front elevation of a combined plumb-bob and rule embodying the principles of my invention. Fig. 2 is an enlarged detail elevation analogous to Fig. 1 and showing only one of the indicators, both ends of the frame being broken away to economize space. Fig. 3 is a longitudinal sectional detail on the line 3 3 of Fig. 2 and looking in the direction indicated by the arrow. Fig. 4 is a cross-section on the line 4 4 of Fig. 2. Referring to the drawings in detail, the frame of my combined plumb-bob and rule is rectangular in plan, the ends 5 and 6 being parallel with each other and at right an les to the sides 7 and 8, said sides being parallel, so that the frame may be used as a right-an gle square, a straight-edge, or a rule. The frame consists of two boards 9 and 10, se cured together by the double dovetail tongues 11, so as to prevent warning. The indicatorrecesses 12 and 13 are formed in the front face of the frame near its ends, and the indicatorplates 14 and 15 are sunk into these recesses and rigidly secured in place. The gravity pointers 16 and 17 are pivotally mounted by screws 18 and 19, inserted through the centers of the pointers through the plates and seated in the body of the frame; The pointers have sharp points 20 and 21 upon their upper ends and weights 22 and 23 upon their lower ends, said Wei hts serving to 0verbal ance the points and l iold the pointers in vertical position. A center line 24 is formed throughout the length of the face of the frame exactly in line with the screws 18 and 19, and the indicator-plates 14 and 15 are graduated or scored in line with the line 24 and crosswise thereof, and the spaces between these right-angled lines may be subdivided to any desired extent, so that the device may not only be used as a plumb-b ob for vertical and horizontal lines, but it may be used to get the degree of inclination. The pointers are sunk in the recesses 12 and 13 below the level of the face of the frame.

In using the instrument as a plumb-bob the operator should note and compare the indications of the pointers at each end of the instrument, as by so doing he may get more,

accurate results than by observing the pointer at one end only, and especially so if one of the pointers should he accidentally bent or fixed against free movement. When the pointers at both ends of the instrument register exactly with the center line 24, the operator may be assured that the work which he is testing is plumb.

I claim An improved plumb-bob, constructed with a beam, comprising a pair of rectangular bars and dovetail tongues connecting said bars, there being a distinguishing-mark formed on the face of one of the bars and extending longitudinally the entire length of the beam, there being shallow recesses formed in the face of the beam on which the mark is arranged, the centers of which recesses are in alinement with the distinguishing-mark, graduated plates removably positibned in said recesses, and gravity-fingers pivotally arranged on said plates within the recesses, the pivotpoints of which plates are in alinement with each other upon the distinguishing-mark and said recesses being of such depth, the removable plates and the gravity-fingers of such thickness, as that the faces of said gravityfingers occupythe same plane with the suriace' of the beam on which the distinguishingmark is formed; substantially as specified.

In testimony whereof I have signed my name to this specification in presence of two subscribing witnesses.

REYNOLDS MODONALD. Witnesses:

JOHN C. Hrenon, META ScHULzE. 

